Shoe stiffener



Patented Oct. 5, 1937 UNITED STATES PATENT OFFICE SHOE s'rmrcmaa Clarence E. Kinney, Wilmington, Del., assignor to Hercules Powder Company. Wilmington, DeL, a corporation of Delaware No Drawing. Application November 28, 1934,

Serial No. 755,231

4 Claims.

This invention relates to an improvement in impregnating composition and to articles impregnated therewith, more specifically box tees for shoes.

cles and will find especially advantageous embodiment in box" toes for shoes, in connection with which the characteristics of the composition will be found highly desirable.

Articles in accordance with this invention will comprise a base, which will be absorptive and may comprise any desirable absorptive material, as felt, woven fabric, paper, or the like, impregnated with the composition in accordance with this in- .vention. More particularly, in the case of box toes in accordance with this invention, such may comprise any suitable absorptive base, such as 2 ance with this invention and shaped or formed as desired in any usual manner.

The composition in accordance with this invention will comprise as an essential ingredient extracted pine wood pitch obtained in connection wit i the production of wood rosin from pine stump wood. The pine wood pitch will comprise oxidized resin acid, oxidized abietic acid, oxidized terpenes, polyphenols, polymerized terpenes and usually more or less ligneous matter.

Compositions for use in the production of impregnated articles, as box toes, in accordance with this invention, will contain in addition to the pine wood pitch the usual ingredients heretofore 40 used inimpregnating compositions for box toes,

such as, for example,.petroleum or oil asphalt, chlorinated rubber, a polymerized vinyl acetate resin, or the like. .Further compositions for the production of box toes in accordance with this 45 invention may contain variously a wax, as Montan wax, rosin, pine oil foots, or other ingredient which may be desirably included to give: to box 55 box toes'for shoes, in which rosin has heretofore Impregnated articles in accordance with this i felt, impregnated with the composition in accordformed a substantial ingredient, the pine wood pitch described may be used in substitution in whole or in part for rosin and to the extent of substitution will decrease, up to entire elimination, thev tendency toward spontaneous combustion.

The pine wood pitch forming the essential ingredient of compositions in accordance with this -invention and of impregnated articles formed therewith, as has been indicated, is obtained in connection with the production of wood rosin from pine wood. The pine wood pitch will comprise oxidized resin, oxidized abietic acid, oxidized terpenes, polyphenols, polymerized terpenes, and

more or less ligneous matter, but will differ somewhat in its specific characteristics, such as acid number, melting point, petroleum ether solubility and content of naphtha and toluol soluble matter, depending upon the method for the recovery of rosin from pine wood used in its production.

As is well known rosin is extracted from pine wood by the use of a, suitable solvent, such as gasoline, after steaming of the wood with live steam to remove volatile oils, such as turpentine and pineoil. Again, volatile oils, as turpentine, and pine oil, are extracted with the rosin without first steaming for their removal.

Following extraction the extract is distilled for the removal of solvent where thewood was subjected to steaming before extraction and for the removal of solvent and volatile oils, as turpentine g0 and pine oil, where the wood was extracted directly without steaming. As the result of distillation a resinous material consisting of a mixture of rosin, oxidized abietic acid, oxidized terpenes, polyphenols, polymerized terpenes'and ligneous matter is obtained; This resinous material may be treated in any one of a number of ways, all

known to the art, for the removal of refined rosin: The residue remaining after the removal of re- 40 fined rosin'and' irfcluding oxidized abietic acid, oxidized terpenes, polyphenols, polymerized ter- I penes and ligneous matter originally present in the extract and comprising a dark colored, hard, resinous mass constitutes thepine wood pitch, the essential ingredient of the impregnating composition and impregnated articles constituting this invention.

. The exact properties of the pine wood pitch obtained as indicated above will depend upon the method used for/original extraction from the wood. When the wood is steamed before solvent extraction, a pine wood pitch is obtained having somewhat different properties from that obtained when the wood is extracted without steaming. A

comparison of the properties of the two pine wood pitches is shown in the following table, in which pitch A is that obtained by extraction of the wood after steaming and pitch B is that obtained by direct extraction without steaming:

Pitch A Pitch B 100 103 91 G. 115 8.0% 1.5% 11.5% 4. 0% Toluol soluble matter 45. 0%

In the practical adaptation of this invention more particularly to, for example, the production of box toes for shoes, the pine wood pitch above described will be combined with any of the usual materials used for the production of box toes, as, for example, asphalt, chlorinated rubber, a polymerized vinyl acetate resin, or the like, and the box toes will be formed in any usual and well known manner. For example, any suitable ab sorptive base, such as a felt, will be impregnated with the composition and formed in any usual manner. For example, where the impregnating composition includes asphalt, the felt will be impregnated by immersion in a molten bath of impregnating composition. Where the impregnating composition contains chlorinated rubber or a polymerized vinyl acetate resin, the impregnation of the felt will be effected through the use of a impregnated articles as, for example, box toes in accordance herewith, either petroleum or coal tar asphalt, of suitable consistency and such as has been used previously in the production of box toes may be used. Chlorinated rubber produced by any well known method and of a viscosity and chlorine content such as has heretofore been used in producing box toes, or as may be desirable may be used, and likewise with respect to polymerized vinyl acetate resins, which may be produced by any well known process for the production of the Vinylite resins of commerce.

For the production of box toes for shoes various proportions of pine wood pitch and asphalt, or of chlorinated rubber, or polymerized vinyl acetate resin, etc., may be used and, as has been indicated, other ingredients, such as Montan wax, pine oil foots, rosin, and the like, may be included.

Typical formulations using asphalt as the base material may be made up on the formulae shown in the following table:

The proportions of ingredients shown ,in the above table may be, .widely varied, using asphalt asthe base material.

be varied within the following ranges:

Percent Asphalt 0-30 Montan wax 0-20 Extracted pine wood pitch 0-10 Rosin -s 60-70 known apparatus.

Thus, the ingredients may- In the production of box toes using any one of the formulae given in the above table, the composition will be rendered fluid by the application of heat. A suitable felt will be saturated by immersion in the composition and subsequently, before the' composition is cooled, suitable shapes will be cut out and formed into box toes in any well known manner and with the use of any well Likewise, the box toe shapes may be cut out; then impregnated and finally shaped.

It will be noted that the inclusion of the pine wood pitch in the above formulae will substantially eliminate any dangerous oxidation or spontaneous combustion of the wood rosin included in the above formulae. Where a petroleum asphalt is used, it will be desirable to include some wood,

rosin, since the pine wood pitch is not entirely compatible with the petroleum asphalt. The inclusion of the pine wood pitch will, however, eliminate dangerous oxidation of the rosin in such quantity as is necessary to be used. On the other hand, where a coal tar asphalt is used, it is not necessaryto use any wood rosin and the pine wood pitch may be used in complete replacement of wood rosin, though generally some rosin will be included.

As further illustrative, for example, where chlorinated rubber is included in the impregnating composition for the production of box toes, chlorinated rubber and the pine wood pitch indicated may be used in widely varying proportions. Likewise, other ingredients, such, for example, as wood rosin, pine oil foots, and the like, may be included'in varying proportions, depending upon the characteristics desired for the box toes. As illustrative, for example, a composition satisfactory for the production of box toes may be made up on the following formula:

It will be appreciated that the'benzol included in the above formula serves as a solvent and enables ready impregnation of felt with the composition. In the production of box toes, felt will be impregnated with the composition in accordance with the above formula and the solvent eliminated. Box toe shapes may be cut from the felt and formed before complete elimination of the solvent, or subsequently by rendering the felt workable by the addition of solvent. If desired the impregnated felt may be rendered workable by heating.

Heretofore in compositions such as that in accordance with the above formula including chlor-'- inated rubber, the presence of rosin has been deemed necessary to impart stiffness and added thermoplasticity. With the inclusion of thepine wood pitch indicated wherethe pine wood pitch replaces rosin to the extent of about 20% or more, dangerous oxidation of rosin will be eliminated. However, in compositions including the pine wood pitch and chlorinated rubber, it has been found non-essential to include rosin, since the desired stiffness and thermoplasticity will be afforded by the pine wood pitch.

Compositions in accordance with this invention, using polymerized vinyl acetate resins together with the pine wood pitch indicated may be made up on" the above formula, illustrative of compositions containing chlorinated rubber, re-

placing the polymerized vinyl acetate resins for the chlorinated rubber and using acetone as the solvent instead of benzol. Where the impregnating composition includes a polymerized vinyl acetate resin the box toe blanks will be cut out and shaped before the impregnated felt is completely dry or after softening with a solvent. 1

What I claim and desire 'to protect by Letters Patent is:

1. A box toe for shoes comprising an absorptive base impregnated with a composition including as an ingredient a resinous material of'higher melting point than rosin and comprising oxidized resin acids, oxidized terpenes, polyphenols and polymerized terpenes remaining as a residue after the separation'of a refined rosin from the crude resinous material obtained by extraction of pine wood.

2. A box toe for shoes comprising an absorptive base impregnated with a. composition including as {ingredients asphalt and a resinous material of higher melting pointtlian rosin and comprising oxidized resin acids, oxidized terpence, polyphenols and polymerized terpenes re-' maining as a residue after the separation of a.

refined rosin from the crude resinous material obtained by extraction of pine wood.

3. A box toe for shoes comprising an absorptive base impregnated with a composition including as ingredients chlorinated rubber and a'resinous material of higher melting point than rosin and comprising oxidized resin acids, oxidized terpenes,

polyphenols and polymerized terpenes remaining as a residue after the separation of. a refined rosin from the crude resinous material obtained by extraction of pine wood.

4. A box toe for shoes'comprlsing an absorptive base impregnated with a composition including as ingredients a polymerized vinyl acetate resin and a resinous material of higher melting point than rosin and comprising oxidized resin acids, oxidized terpenes, polyphenols and polymerized terpenes remaining as a residue after the separation of a re fined rosin from the crude resinous material obtained by extraction of pine wood.

' CLARENCE E. KINNEY. 

